Orbital Metastasis of Pancreatic Cancer Not Detected on MRI at the Time of Clinical Presentation.

Background/Aim: The orbit is a rare site for metastasis from pancreatic cancer, and diagnosis can be challenging when early imaging findings are subtle. We report a case of orbital metastasis initially undetectable by magnetic resonance imaging (MRI) but subsequently managed with radiotherapy. Case Report: A man in his 60s with metastatic pancreatic adenocarcinoma developed right-sided periorbital pain and hypoesthesia during chemotherapy. Initial brain and orbital MRI showed no evidence of metastasis, and symptoms were managed as suspected trigeminal neuralgia. Five months later, the patient developed diplopia; follow-up MRI revealed a soft tissue lesion at the right orbital apex with high signal intensity on fat-suppressed T1-weighted imaging, leading to a diagnosis of orbital metastasis. The patient underwent palliative radiotherapy, resulting in significant alleviation of pain and diplopia. Conclusion: Orbital metastasis from pancreatic cancer may present with morphological changes undetectable on initial MRI, highlighting the importance of a high index of clinical suspicion and serial imaging follow-up for unexplained neurological symptoms. Palliative radiotherapy is an effective modality for achieving symptomatic relief and improving quality of life in this rare manifestation. Clinicians should consider orbital metastasis when new-onset periorbital symptoms occur in patients with advanced pancreatic cancer.